HomeMy WebLinkAboutIII.3. Site Utility StudyWMENSun-Tech Engineering, Inc.
1600 West Oakland Park Boulevard
Fort Lauderdale, Fl. 33311
I.m.ginecrs Q Planners 0 Surveyors (954) 777-3123 /Fax (954) 777-3114
E-mail: suntech@suntecheng.com
October 21, 2009
City of Miami
Attn: Roberto Lavernia
444 S.W. 2nd Avenue
Miami, FL 33130
RE: YMCA CARVER MUSP
STATEMENT OF CONSISTENCY -SITE UTILITY STUDY
STE PROJECT No. 05-2978
Dear Mr. Lavernia:
Sun -Tech Engineering, Inc has reviewed the revised site plan and we confirm that
the Utility Study prepared in 2007 is still accurate and valid for the revised MUSP.
The drainage characteristics have changed but have not compromised the ability to
construct the proposed development.
If you have any questions or require additional information, please do not hesitate
to contact me.
Sincerely,
SUN -TECH ENGINEERING, INC.
��VV
�
William C. Lips, P.E.
Florida Registration No. 61741
Cc: Oscar Sol, The Carlisle Group
Iris Escarra, Greenberg Traurig P.A.
Heidi Henderson, STE
K:\Project Docs\05-XXXX\05-2978 YMCA Village Carver\Letters\Lettel'008 City MUSP-Site Utility.doe
Vow MCA VILL, AGE CAR_V ER
401 N.W. 71St STREET
MIAMI, FLORIDA 33150
SITE UTILITY STUDY
APRIL 2007
PREPARED FOR:
BIS CAYNE HOUSING GROUP, INC.
150 SE Second Ave, Suite 1202, Miami, Fl, 33131
THE CARLISLE GROUP
2950 SW 27"' AVENUE, SUITE 200, MIAMI, FLORIDA 33133
PREPARED BY:
is
SUN—TECH ENGINEERING, INC.
1600 WEST OAKLAND PARK BOULEVARD
FORT LAUDERDALE, FLORIDA 33311
954-777-3123 954-777-3114 (fax)
www.suntech &suntechenll.com
YMCA Village Carver Site Utility Study April 2007
I.
INTRODUCTION
The project site is located at 401 NW 71" Street, Miami, Florida 33150 and
has a net area of 6.81 acres. An affordable elderly & family residential
community is proposed consisting of three separate phases. Phase I consists
of a 9 story elderly apartment building having 112 units and an attached
parking garage. Phase II consists of an 8 story -98 unit elderly apartment
building with an attached parking garage and Phase III consists of an 11
story -98 unit family apartment building with an attached parking garage.
Driveway connections are proposed onto NW 71St Street and NW 72"d
Terrace.
II. DRAINAGE SYSTEM
General Runoff Characteristics
The proposed site does not include a lake or an offsite drainage connection
so all stormwater runoff shall be collected and stored within on-site
exfiltration trench. The drainage system must be designed to accommodate
the traditional runoff generated from the horizontal surfaces, and in addition
Miami -Dade DERM requires that for high rise buildings, the proposed
drainage system also take into account runoff from one-third of the largest
vertical building face. Preliminary drainage calculations are shown in
Exhibit A.
Site Coverage Data
Horizontal Areas
AREA ac.
PERCENT
Building
0.94
14%
Paved (On grade Parking & Roads)
2.48
36%
Sidewalk
0.86
13%
Garage
1.03
15%
Green (Landscaping,)
1.50
32%
TOTAL
2.44
100%
Vertical Areas (1/3 of the building faced
Phase I Tower (1/3 x 205' x 95')
0.15
Phase II Tower (1/3 x 205' x 95')
0.15
Phase III Tower (1/3 x 205'x 95')
0.15
TOTAL
0.45
TOTAL IMPERVIOUS AREA (including vertical areas) 5.65
79%
PERVIOUS AREA
1.50
21%
TOTAL RUNOFF AREAS
7.15
100%
Page 2 of 5
YMCA Village Carver Site Utility Study
April 2007
Permit Criteria
South Florida Water Management District (SFWMD)
Per the above site coverage data, this project requires an Environmental
Resource Standard General Permit, in accordance with the SFWMID Permit
Information Manual, Volume IV, Chapter 40E-40.
Miami -Dade County Dept. of Environmental Resources Management
DERM
In accordance with Section D-4 of the Miami -Dade Public Works Manual,
the drainage system must be designed to store the required water quality
treatment volume or the runoff generated from the 5 year -1 hour storm
event, which ever is greater. The minimum parking grade must be above
the 5 year -1 hour storm elevation. These calculations are shown on Exhibit
A.
Note: DERM requests that the drainage systems for the parking levels
below roof, not subject to direct rainfall, be kept separate from the site
drainage.
Minimum Grade Criteria
Parking Lot/Road Grade- Min. of: 5 year -1 hour storm elevation
Moot below back of sidewalk grade
Minimum Perimeter Grade- 25 year -3 day storm elevation
Finished Floor Elevation- Min. of 100 year -72 hour storm elevation
8" above crown of City Rd.
FEMA Base Flood Elevation(See Exhibit B)
Project Discharge
This project does not have an offsite drainage connection unless a drainage
well is permitted. If drainage wells are permitted at this location, the
drainage system can be designed to store the required water quality
treatment volume and then discharge any additional runoff directly into the
drainage well.
Drainage Wells
Drainage Wells are regulated by the Department of Environmental
Protection and the main limiting criteria permitting their use is such that the
well casing shall penetrate a zone containing a minimum of 10,000 mg/L
Total Dissolved Solids (TDS). A test hole has been drilled and tested to a
depth of 200 feet and the minimum TDS was not obtained. Due to the
excessive costs to drill a well casing below 200 feet, the test well was
abandoned without reasonable assurance of the minimum TDS.
Page 3 of 5
YMCA Village Carver Site Utility Study April 2007
III. WATER DISTRIBUTION SYSTEM
Miami -Dade Water and Sewer Department owns and operates the public
water mains in this area. The existing water mains adjacent to the project
are as follows: NW 5th Avenue- Twenty (20) inch
NW 71" Street- Eight(8)inch
NW 72"d Terrace- Six (6) inch
Pursuant to a request for Service Agreement from MD-WASD, "the
preliminary "Points of Connection (P.O.C.)" were determined by MD-
WASD dated January 29, 2007 and state the following:
"Connect to an existing twenty (20) inch water main in N. W. Sth
Avenue and N. W. 71" Street and extend a sixteen (16) inch w.m.
easterly in N. W. 71" Street to the southeast corner of the property,
interconnecting to an existing eight (8) inch w.m. at that location.
Any public water main extension within the property shall be
twelve (12) inch minimum diameter. If two (2) or more fire
hydrants are to be connected to a public w.m. within the property
then the water system shall be looped with two (2) P.O. C.
Separate connections for fire lines and fire hydrants are required".
Phase I water and fire service is proposed directly from the proposed 16"
water main within N.W. 71" Street including a 4" water service for the
apartment building, a 6" fire service, and one fire hydrant. A twelve (12)
water main extension is proposed on-site, from which one fire hydrant is
proposed, maintaining a maximum distance of 300 feet between hydrants.
Phase II & III shall extend and loop the twelve (12) water main to the
existing twenty (20) inch water main within NW 5th Avenue. Water
services, fire services and fire hydrants shall be provided to Phases II & III
by the looped on-site twelve (12) inch water main.
The estimated average daily water consumption from this project is 61,600
gallons per day (gpd), as calculated in Exhibit C.
Page 4of5
YMCA Village Carver Site Utility Study April 2007
IV. SANITARY SEWER SYSTEM
MD-WASD owns and operates an eight (8) inch gravity sewer main in
N.W. 71St Street and N.W. 72"d Terrace. Pursuant to the above referenced
preliminary P.O.C., MD-WASD determined the following:
"Connect to any of the existing eight (8) inch gravity sewers in
N. W. 71" Street and/or N. W. 72 Terrace. "
Phases I & II which are adjacent to N.W. 71St Street shall connect to the
existing 8" gravity sewer main within N.W. 71St Street. Phase III, located
in the northeast corner of the site, shall connect to the existing 8" gravity
sewer main within N.W. 72"d Terrace.
The estimated average daily sewage flow from this project is 61,600 gpd, as
calculated in Exhibit C.
V. SOLID WASTE MANAGEMENT
On -Site receptacles for refuse and recyclables are proposed within each of
the buildings. Regular pick-up service shall be provided by either the City
of Miami Solid Waste Department and/or an approved private hauling
company.
Page 5 of 5
SUN -TECH ENGINEERING, INC. DATE: 4/11/2007
1600 W. OAKLAND PARK BLVD. REV:
FORT LAUDERDALE, FL 33311 BY: KKS
EXHIBIT A
SURFACE WATER MANAGEMENT CALCULATIONS FOR
YMCA VILLAGE CARVER - ULTIMATE BUILD -OUT
HORIZONTAL SURFACE
LAND USE BREAKDOWN
LAND USE
AREA
PERCENT
BUILDING
0.94
14%
PAVED AREAS
2.48
36%
SIDEWALK
0.86
13%
GREEN
1.50
22%
GARAGE
1.03
15%
TOTAL
6.81
100%
VERTICAL BUILDING FACES
BUILDING
WIDTH
HEIGHT
1/3 x AREA (AC.)
Phase I Tower
Phase II Tower
Phase III Tower
205
205
60
95
95
95
0.15
0.15
0.04
TOTAL
0.34
ADJUSTED
GRADING PARAMETERS
LAND USE BREAKDOWN*
LAND USE
AREA
PERCENT
FROM
TO
BUILDING
1.28
18%
11.5
100
PAVED AREAS
2.48
35%
9
11
SIDEWALK
0.86
12%
10
11.45
GREEN
1.50
21%
8
11
GARAGE
1.03
14%
17.00
100
TOTAL*
7.15
100%
TOTAL RUNOFF AREAS*
LAND TYPE AREA PERCENT
IMPERVIOUS 5.65 79%
PERVIOUS 1.50 21%
TOTAL 7.15 100%
*DERM requires additional runoff generated from the vertical building
faces be incorporated into the surface water management system.
Exfiltration Trench
Total Exfiltration Volume
V(ac-in)= L x [K x (H2W + 2H2DU-D�2 + 2H2Ds) + (1.39 x 10"4)WD„l
= 89.2 = 7.44 ac -ft
Trench Stage -Storage Calcs.
Stage (ft)
Storage (ac -ft)
3
0.00
3.5
0.93
4
1.86
4.5
2.79
5
3.72
5.5
4.65
6
5.58
6.5
6.51
7
7.44
Trench Characteristics
L= 1000
W= 4
KA,g= 5.31 E-04
H2= 6.00
Du= 4.00
DS 9.00
STAGE -STORAGE CALCULATIONS
Assume Linear Progression for all Areas
Stage
Area acres
Storage
(ft-NGVD)
(ac -ft)
PAVED AREAS
SIDEWALK
GREEN Total
3.0
0.00
0.00
0.00
0.00
0.00
3.5
0.00
0.00
0.00
0.00
0.93
4.0
0.00
0.00
0.00
0.00
1.86
4.5
0.00
0.00
0.00
0.00
2.79
5.0
0.00
0.00
0.00
0.00
3.72
5.5
0.00
0.00
0.00
0.00
4.65
6:0
.0.00
0.00
0.00
0.00
5.58
6.5
0.00
0.00
0.00
0.00
6.51
7.0
0.00
0.00
0.00
0.00
7.44
7.5
0.00
0.00
0.00
0.00
7.44
8.0
0.00
0.00
0.00
0.00
7.44
8.5
0.00
0.00
0.25
0.25
7.50
9.0
0.00
0.00
0.50
0.50
7.69
9.5
0.62
0.00
0.75
1.37
8.15
10.0
1.24
0.00
1.00
2.24
9.06
10.5
1.86
0.30
1.25
3.41
10.47
11.0
2.48
0.60
1.50
4.57
12.46
11.5
2.48
0.86
1.50
4.84
14.81
Project Location Hydraulic Details
Design Water Level= 3.00
Allowable Discharge* = N/A csm = Total Area x N/A / 640 =
* DISCHARGE/POSIT/VE OUTFALL NOT AVAILABLE
Design Storm Rainfall Amounts (in.)
Storm
Frequency
DERM
inches
24 hr
72 hr
5 year
7.1
12.72
10 year
8.7
17.88
25 year
14.6
100 year
19.8
Soil Storane Calculation
N/A cfs
A. Total Pervious Area = 1.50 acres
B. Depth to Water Table = 6.5 feet
C. From SFWMD Permit Information Manual, Vol. IV, Figure E-1, For
'Developed/Compacted Normal Typical Sandy(Coastal)', the Cumulative Available Soil
Storage is:
Sp = 8.18 inches
D. Site Soil Storage = Sp x (Pervious Area/Total Area)
1.72 inches
Water Quantity Calculations
A. Calculate the Runoff in Inches.
Q= (Rainfall - 0.2 x Soil Storage)2 / (Rainfall + 0.8 x Soil Storage)
QSyr-1day=
5.39
inches
Q10yr-1dy
6.93
inches
Q25yr-3dy=
12.72
inches
Q100yr-3day
17.88
inches
B. Calculate the Runoff Volume
V= Q x Project Area (1 ft / 12 in)
V5yr-1day= 3.21 ac -ft
V1oyr-1day= 4.13 ac -ft
V25yr-3dy 7.58 ac -ft
V100yr-3day 10.66 ac -ft
3
C.
Using the stage -storage chart and the runoff
volumes calculated above, the corresponding
stages can be interpolated.
Stage5yr-1day= 4.73 ft
Stageloyr-1day= 5.22 ft
Stage25yr-3dy= 8.73 ft
Stage,00yr-3day= 10.55 ft
Water Quality Calculations (Note: Ignore Vertical Building Faces, include garage parking areas)
A. Compute the first inch of runoff from the entire site.
= 1 inch x Total Area x (1 ft / 12 in)
0.57 ac -ft
B. Compute 2.5 inches times the percentage of imperviousness.
a. Site Area (SA), for water quality pervious/impervious calculations onl
SA= Total Area - (roof + lake)
5.87 Acres
b. Impervious Area (IA), for water quality pervious/impervious calculations PWI
IA= Site Area(SA) - Pervious Area
= 4.37 Acres
C. Percentage of imperviousness for water quality
%imp= (IA / SA) x 100%
74.44 %
d. For 2.5 inches times percentage of imperviousness
2.5 inches x %imp
1.86 inches
e. Compute volume required for quality detention
inches to be treated x (total - lake) x (1 ft / 12 in)
= 1.06 ac -ft (CONTROLS)
C. Since 2.5 inches times the percentage of impervious is greater than the first inch of
runoff over the entire site, the volume to be treated is:
Volume to be treated = 1.06 ac -ft
Interpolating from the Stage -Storage Table, the Volume to be treated is met at a stage
of:
Stage (Water Quality) = 3.57 ft
4
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SUN -TECH ENGINEERING, INC. DATE: 4/20/07
1600 W. OAKLAND PARK BLVD. REV.:
FORT LAUDERDALE, FL 33311 BY: WCL
EXHIBIT C
ESTIMATE OF WATER & WASTEWATER FLOWS FOR
YMCA VILLAGE CARVER
AVERAGE DAILYFLOW
FLOW(gpd) TOTAL
TYPE OF USE NO. OF UNITS PER UNIT FLOW(apd)
Residential Apartments 308 200 61,600
AVERAGE DAILY FLOW = 61,600 gpd
0.062 mgd
ESTIMATED PEAK FLOW
POPULATION (P) = NO. UNITS x 2 PEOPLE/UNIT x 1/1000
= 0.462 (THOUSANDS)
PEAKING FACTOR= (18 + p112) / (4 + pv2)
4.0
PEAK FLOW = ADF X PEAKING FACTOR
245,885 gpd
0.246 mgd
Notes:
1, gpd = gallons per day
2. mgd = millon gallons per day
3. No industrial wastewater is anticipated to be generated.
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